import java.util.Scanner;

public class TestDemo {
    public static void main1(String[] args) {
        Scanner in = new Scanner(System.in);
        String s = in.nextLine();
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < s.length(); i++) {
            char ch = s.charAt(i);
            if (!sb.toString().contains(ch + "")) {
                sb.append(ch);
            }
        }
        System.out.println(sb.toString());
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        while (in.hasNextLine()) {
            String s = in.nextLine();
            StringBuilder sb = new StringBuilder();
            char[] ss = s.toCharArray();
            char[] ss2 = new char[100];
            int j = 0;
            int count = 0;
            for (int i = 0; i < ss.length; i++) {
                for (j = 0; j < ss2.length; j++) {
                    if (ss2[j] != ss[i]) {
                        continue;
                    } else {
                        break;
                    }
                }
                if (j == ss2.length) {  //如果相等则表明走完了ss2,表明没重复
                    ss2[count] = ss[i];
                    count++;
                }
            }
            for (int i = 0; i < count; i++) {
                sb.append(ss2[i]);
            }
            System.out.println(sb.toString());
        }
    }
}
